It is common for electrical systems to include various types of interconnects. For example, the interconnects can include input/output (I/O) pins, I/O bumps, ball grid array (BGA) elements, I/O vias, and/or other electrical structures implemented on packages for integrated circuits, printed circuit boards, electrical sockets, electrical connectors, electrical interposers and/or other types of electrical systems. In such structures, the conductors are often arranged in two-dimensional arrays in order to efficiently use the available area. As such, each interconnect is likely adjacent to multiple other interconnects.
An important factor in designing such structures is to control (e.g., minimize) crosstalk between the interconnects. For example, signals carried on one electrical interconnect can manifest as noise on other interconnects. The noise can become more pronounced (and potentially more detrimental to the efficacy of the electrical system) as data rates increase, voltage margins decrease, etc. For example, in many high-speed electrical systems, crosstalk can be strongest in structures, such as via arrays, connectors, and interfaces between packages and printed circuit boards (PCBs) (e.g., between BGAs and sockets).
One traditional approach to reducing crosstalk in these types of structures is to separate the interconnects as much as possible and/or to add return-path interconnects. The increased spacing can minimize inductive and/or similar effects (i.e., such effects typically drop off rapidly with distance), and surrounding signal interconnects with return-path interconnects can effectively provide shielding. However, both approaches can appreciably reduce the number of interconnects that can fit in a particular area, thereby potentially reducing signal density, increasing cost, etc. Some other traditional approaches include carefully assigning particular signals to particular interconnects to effectively separate likely interfering signals, or reorienting interconnects away from a two-dimensional array formation to increase spacing, shielding, etc. These other traditional approaches typically increase complexity of signal routing and design, and can often be incompatible with other standard methodologies.